In a cylindrical grinding machine, having a rotatable grinding wheel carried in a wheel head and surrounded by a wheel gaurd, a wheel gaurd hood is often employed to act as an adjustable gaurd, to take up the voids between the grinding wheel and the relatively fixed wheel gaurd as the grinding wheel changes size due to wheel wear and dressing cycles. The wheel gaurd hood is most generally swingably attached to a swing axis at the the top of the wheel gaurd and is secured to the wheel guard by both the swing pivot stud and a bolt passing through the hood at a point distal from the swing axis. The bolt passes through a slot in the hood, which slot is arcuately formed about the swing axis, so that as the bolt is loosened, the hood may be pivoted and reclamped by the bolt. The hood is usually adjusted by an operator having to manually unclamp, reposition and clamp the hood.
The hood tends to prevent coolant from escaping from the periphery of the grinding wheel, splashing where undesired, and further, the hood tends to entrap wheel fragments which may occur in the event of wheel breakage. Naturally, since the wheel gaurd is a fixed structure sized to carry the maximum grinding wheel, the "voids", or clearances, between the wheel and the wheel gaurd, become accentuated as the wheel is reduced in size, thus intensifying any tendencies toward occurrence of the aforementioned hazards.
Since hoods are generally adjusted by the machine user in manual fashion, they are not in the closest proximity to the wheel at all times as they are only adjusted periodically while the wheel is reducing in size continually. Thus, a potential hazard may be permitted to exist by the machine user by his not adjusting the hood as often as needed.
Purely mechanical means for automatically adjusting the hood in relation to wheel head position on the base, is not too practical for a machine which must grind a variety of part sizes. That is, a mechanical system could possibly be devised where all the system parameters are fixed, including the part size. For greatest adaptability, however, applicant has obviated many of the difficulties inherent in the prior art devices by his novel design which employs a motor means for automatically powering a wheel gaurd hood into close proximity with a grinding wheel circumference. In addition, many state of the art machines employ wheel dressing means having automatic compensation devices which may be powered from a motor control source. Applicant's invention provides a system which may receive like pulses from a motor control source at time of wheel dressing, providing a contemporaneously moveable wheel guard hood in relation to a dressed wheel, or in the alternative, the wheel guard hood may be configured so that its point which is nearest the wheel, may be powered from a pivot point which is elsewhere on the hood, and thus it may be desirable to move the hood by motor signals means in a predetermined ratio to a wheel dressing motor means.
It is therefore an object of the present invention to provide an automatically controlled wheel hood adjusting apparatus, which is capable of being powered from a motor control source in ratio to the signals of a wheel dressing apparatus.